Climate variability and trends in the reproductive habitat of the critically endangered hooded grebe

Abstract

The population of the critically endangered hooded grebe (Podiceps gallardoi) has decreased drastically during recent decades. The effects of climate change on their reproductive area (Southern Patagonia) have been proposed as one of the potential causes of their critical situation. However, there is much uncertainty about climate variability and climate trends at local scales in Patagonia, and their effects on the hooded grebe habitat. Variability and trends in temperature, precipitation, and wind from 1960 to 2016 in one of the most important reproductive areas of hooded grebe ? the Lake Strobel plateau ? were analysed. A Landsat satellite image series (1973?2016) was used to evaluate changes in lake area in the region. Generalized linear models were used to analyse the relationship between the variation in lake area and climatic variables, including the Antarctic Oscillation Mode (AAO) index, which is the most important year to year pattern in climate variability at high latitudes of the Southern Hemisphere. High inter-annual variability and increasing coefficients of variation in precipitation and wind were found, as well as a significant positive trend in temperature. Total lake area, as well as the area specifically used by hooded grebe to reproduce, decreased significantly over time, with high inter-annual variability. Variation in lake area was significantly correlated with variation in precipitation, and with the AAO index. The loss of reproductive habitat may force the hooded grebe to use sub-optimal environments, such as lakes with lower food supply, lower macrophyte cover, and less protection from wind ? a potential major handicap for this declining species. Information on lake variation in response to climatic variability could be used to guide hooded grebe conservation strategies, directing more resources and special efforts to those reproductive lakes that are more resilient to the effects of climate fluctuations.